Societal demands for greater automotive fuel economy, lower environmental impact and improved performance have produced a trend towards lightweighting in automobiles. In this context, the effect of car mass and size on occupant safety is receiving considerable attention in the literature. Concerns have been raised about the safety of occupants of smaller, lighter cars involved in accidents with larger, heavier vehicles. The evidence supporting these concerns comes from crash data of existing steel-bodied cars.In this paper, the possibility of using an aluminum body structure to reduce automobile mass is explored. The use of lightweight aluminum provides the opportunity for a larger low mass structure than could be achieved by traditional steel body construction. This paper provides technical data related to the energy-absorbing characteristics of aluminum components. It also suggests that proper alloy selection and proper design can result in a more mass-efficient energy-absorbing structure in the lightweight car. This structure, along with safety devices available today, enable the manufacture of a vehicle providing at least the same level of occupant safety as heavier cars of the past.